That's what advertising agencies are telling brands regarding the upcoming Facebook Reactions launch, which will allow users of the social media platform to express a wider array of emotions than merely approval.

The reason: Negative reactions can be good for business, even if users won't always give a thumbs-up to their advertising campaigns.

"Facebook has already provided a robust set of metrics about how a consumer interacts with your post," said The Barbarian Group director of analytics Will Sandwick. "Besides feedback like hiding and reporting posts as spam, from a consumer experience standpoint, it gives more ways for consumers to engage."

After years of Facebook users asking for more ways to express themselves besides "like," Facebook announced in early October that it would be adding six more options to let users rate posts. The new emotions -- love, haha, yay, wow, sad, angry -- aren't exactly as blatant as saying you dislike something. However, it does allow people to show a bit more of what they are feeling. It is being tested in Ireland and Spain, but will expand globally eventually, though the company hasn't yet said when.

Content monetization platform Skimlinks CEO Alicia Navarro believes that having more data on reaction capabilities can give Facebook a wider set of nuances to train their algorithms that determines what shows up on news feeds.

"Advertisers don't want to be advertising to entities that are not human," she said. "They also don't want to be wasting their advertising dollars on people who are not interested. Having that extra set of data is going to make advertisers more interested."

Sandwick said that it's the granular data that goes beyond a basic "like" that brands are interested in, anyway. Sure, a post's popularity can be boosted by the number of "likes," but he said what agencies and companies are really interested in are the comments and shares.

Deutsch executive vice president and director of digital strategy Zach Gallagher said the comments show that someone cared enough about the post to take time out to write something.

Plus, having a negative reaction to a campaign isn't necessarily a bad thing, Gallagher added.

"We love to see peer-to-peer sharing more than just a mild 'like' or just getting enough interaction to get someone to click a like button or smiley face," he said. "We like ideas getting their own gravity by being shared. A big way we do that is to try and put work out there that has a little bit of tension, that could be a bit polarizing for one audience."

For example, Deutsch launched an Angel Soft campaign for single mothers that wished them a happy Father's Day for being "soft and strong supporting parents." Gallagher said a group that supported men's rights became angry, saying that Angel Soft was taking away the one holiday for men. Because social media can spread sentiment far and fast, Gallagher said that the fringe group became vocal even though they didn't represent the sentiment of the majority.

"There is an overpresent minority that tends to talk a lot more and rile things up in a lot of people," Gallagher said. "They're going to get our idea in front of people that don't agree with them, and share the ideas that our brand shares. (Those people who don't agree) are who we're looking to connect with. If there are people that don't share our values, that's OK."

Sandwick pointed out other campaigns that took negativity and turned them positive, including agency Droga5's "Honey Maid: Love" ad. The company took anti-LGBT comments made on a previous Honey Maid ad called "This is Wholesome" that featured gay and lesbian couples, printed them out and created a paper sculpture of the word "love" out of the hateful sentiments. It's been viewed more than 4.3 million times on YouTube. The original ad has now been viewed almost 8.2 million times.

"I think it's always going to be critical not to let consumers dictate how brands behave, but how brands listen to consumers should dictate what is important to them," Sandwick said.

Michelle Castillo

Michelle Castillo is a staff writer for CNBC Digital, covering advertising and digital media. Previously, she was a digital media reporter for Adweek, and has covered media and entertainment for publications including the Los Angeles Times,...